imc

Let $A$ be the age of Ana and $B$ be the age of Bonita. Then, $$A-1=5(B-1)$$ and $$A=B^2.$$ Substituting the second equation into the first gives us $$B^2-1=5(B-1).$$ By using difference of squares and dividing, $B=4.$ Moreover, $A=B^2=16.$ The answer is $16-4=\boxed{12}$.